The document discusses the anatomy and physiology of the brain. It describes the main parts of the brain as the cerebrum, cerebellum, and brain stem. The cerebrum is the largest part and is divided into four lobes that control functions like movement, sensation, vision, and language. The cerebellum aids in movement coordination and balance. The brain stem consists of the midbrain, pons, and medulla, and controls vital functions like breathing and heart rate. Other parts discussed include the thalamus and hypothalamus, which regulate sensation and autonomic body processes respectively.

1. The Anatomy and Physiology of
Brain Sarita Sharma
Associate Professor
MMCP, MMDU

2. Organs
CNS:
 Brain
 Spinal Cord
PNS:
 Nerves
ANS

3. Brain
 It is one of the largest organs in the body, and
coordinates most body activities.
 It is the center for all thought, memory,
judgment, and emotion.
 Each part of the brain is responsible for
controlling different body functions, such as
temperature regulation and breathing.

4.  The brain is contained in skull & weighs 1300 - 1400 g
 made up of about 1000 billion neurons & each neuron is
surrounded by about 10 glial cells (neuroglia ).
 Neurons cannot multiply & many neurons are lost everyday
in life but glial cells can multiply throughout the life.
 Brain is also covered by “Meninges” like spinal cord---outer
duramater, middle arachnoidmater & inner piamater

5. Cerebrum
cerebellum

6. Ventricles of the brain
 There are certain cavities in the brain called as “ventricles”.
 These ventricles are filled with CSF.
 There are 4 ventricles of brain
2 lateral ventricles
in two hemisphere
of the brain
3rd lies between
hypothalamus &
thalamus
4th between brain stem &
cerebellum
& is continuous with the
central cavity of spinal
cord

8. Parts of brain:
Cerebrum Cerebellum
Brain
stem
Diencephelon
(1)Medulla
(2)Pons
(3)Mid brain
(1) Thalamus
(2) Hypothalamus
(3) Epithalamus &
Pineal gland
Right
cerebral
hemisph
ere
Left
cerebral
hemisph
ere

10. (A) Cerebrum
 It is the largest section of the brain
 It is located in the upper portion of the brain and is the area
that processes thoughts, judgment, memory, problem solving,
and language, imaginations.
 Cerebral cortex – the superficial layer of the cerebrum is “gray
mater” & this is 2-4 mm thick called “Cerebral cortex ” contains
billions neurons.
 During embryonic development when the brain size increases
rapidly, the gray mater of the cortex enlarges much faster than
deeper white mater so as result cortical region roles & fold
upon itself.

11.  The folds are called “gyri” or “convolutions”
 The deepest grooves between the folds are called “fissures”
 The shallower grooves between folds are called “sulci”
 The most prominent fissure, the longitudinal fissure,
separates the cerebrum into right & left halves called
“cerebral hemispheres”. Each hemisphere has 4 lobes.
 The cerebrum is subdivided into the left and right Both
hemisphere are connected by a bridge of nerve fibers that
relay information between 2 hemisphere called “corpus
callosum”

13.  Left hemisphere controls right side of the body
 Right hemisphere controls left side of the body

14. Lobes of Cerebrum

15. Lobes of Cerebrum
1. Frontal lobe: Most anterior portion of the cerebrum (under
forehead) “central sulcus” separate frontal & perital lobe.
 controls motor function, personality, and speech
• Like Center of reasoning, Planning, some parts of speech,
movement, Emotions, problem solving.
Also called as “motor cortex”

16.  2. Parietal lobe: The most superior portion of the
cerebrum(top of head),
 receives and interprets nerve impulses from sensory receptors
and interprets language.
• Receives sensory input from the skin. (touch, pressure,
temperature, & pain)
 Also called as “sensory cortex”

17.  (3) Occipital lobe: The most posterior portion of the
cerebrum (back of the head),
• Receives input from the eyes & controls vision.
• Also called as “visual cortex”.

18.  4. Temporal lobe: The left and right lateral portion of
the cerebrum(on the sides of your head above your ears),
 controls hearing and smell
 Also called “Auditory cortex”

20. Functions of cerebrum:
 (1) Motor functions like control of voluntary movements.
 (2) sensory functions like perception of pain, temperature,
touch, hearing, taste, & smell.
 (3) control of intelligence, speech, memory & learning etc.

21. (B)Cerebellum
 Second largest portion of the brain
 Located beneath the posterior part of the cerebrum
 A deep groove known as “transverse fissure”
separates cerebrum to cerebellum.
 Aids in coordinating voluntary body movements and
maintaining balance and equilibrium

22. External Structure
 The external surface , called cerebellar cortex, look like
butterfly, constricted area called “vermis”
 The lateral wings or lobes called cerebellar hemisphere
that is interconnected by a narrow portion called vermis.
Each hemisphere
consists of lobes
separated by deep
fissures.

23.  A part of the human brain
that lies in the posterior
cranial fossa , inferior to
occipital lobes.
10% weight of entire
brain.
50% of neurons.

24. Divisions & layers of cerebellum
(1) Anterior lobe both regulate subconscious aspects
of skeletal muscle movements
(2) Posterior lobe
(3) Flocculonodular lobe – on the inferior surface maintain
equilibrium and balance
 Superficial layer of cerebellum called ”cerebellar cortex” consist of
gray mater, series of slender & parallel folds called “folia”.
 Deep to gray mater white mater called “arbor vitae” resemble to
branch of tree.
 Even deeper white mater are”cerebellar nuclei”, region of the gray
mater having axons carrying impulses from cerebellum to other
parts of brain.

25. Flocculonod
ular lobe
folia

26. Cerebellar peduncles:
3) Inferior cerebellar
peduncle is a thick rope-like
strand that occupies the
upper part of the posterior
district of the medulla
oblongata
2) Middle cerebellar
peduncles connect the
cerebellum to the pons.
1) Superior cerebellar
peduncle is a paired
structure that connects the
cerebellum to the
midbrain.
3 paired Attach the cerebellum to
brain stem
These bundles of white mater
consist of axons that conduct
impulses between the cerebellum &
other parts of the brain
connect the cerebellum to the brain stem. There
are six cerebellar peduncles in total, three on each
side:

28. Functions of cerebellum:
(1) Coordinate contractions of skeletal muscles
(2) Regulate posture & balance
(3) May play a role in cognition/learning from experiences &
language processing

29. (C) Brain Stem
 Consists of:
 (1) Midbrain
 (2) Pons
(3) Medulla oblongata
 Superiorly continuous with
Diencephalon
 Inferiorly continuous with spinal cord.
 Posteriorly pons and medulla is separated by fourth ventricle.
 Midbrain, pons and medulla connected to cerebellum by superior,
middle and inferior cerebellar peduncle resp.

30. (1)Mid brain
 The midbrain or mesencephalon exten
ds from the pons to the diencephalon &
about 2.5 cm long.
 It acts as a pathway for impulses to be
conducted between the brain and the
spinal cord.
 associated with vision, hearing, motor
control, sleep/wake, arousal (alertness),
and temperature regulation.
 Screening of information before it reach
high brain structure

31. Functions of mid brain:
 The midbrain serves important functions in motor movement,
particularly movements of the eye, and in auditory and visual
processing.
 Dopamine produced in the substantia nigra and ventral
tegmental area plays a role in excitation, motivation.
 The midbrain helps to relay information for vision and hearing.

32. (2) Pons:
 means bridge—connects the cerebellum
to the rest of the brain.
 lies between midbrain above and
medulla below in front of
cerebellum.
 Like medulla it also sensory tract and
motor tract.
 Contains nuclei that deals with
respiration, swallowing, bladder
control, hearing, equilibrium, eye
ball movements, facial
expressions etc.

33. (3) Medulla oblongata
 Lowermost part of the brain stem &
continuation of the superior portion of
spinal cord.
 Situated at the base of the skull/ starts
from foramen magnum & extends to the
inferior border of the pons, a distance of
about 3 cm.
 The ascending & descending sensory &
motor white mater tracts (nerves)
connecting brain to spinal cord pass
through medulla oblongata.

34.  Its very important because many “regulatory centers ” are
located here
 (1) The cardiovascular center: regulate the heart rate, force of
heartbeat & diameter of blood vessels.
 (2) The medullary rhythmicity center: responsible for
maintaining basic rhythm of breathing.
 (3) The vasomotor center: regulate blood pressure.
 (4) others: vomiting, swallowing, cough, hiccupping & sneezing
etc.
 5 pairs of cranial nerves originates from the nuclei located in
medulla oblongata.

35. (D)Diencephelon

37. (1) Thalamus
 Contain mass of nerve cells.
 Thalamus means “inner room” in Greek, as it sits deep in the
brain at the top of the brainstem.
 The thalamus is called the gateway to the cerebral cortex, as
nearly all sensory inputs pass through it to the higher levels of
the brain.
 It makes up 80% of diencephalon.
 Important relay station for all Incoming
sensory nerves from periphery/ spinal
Cord with different impulses of pain,
temperature, Touch, pressure are conveyed to thalamus
first than Go to cerebrum.

38.  This information is relayed from thalamus to cerebrum through
thalamic nuclei:
(1) Median geniculate nucleus—related to hearing
(2) lateral geniculate nucleus—related to vision
(3) Ventral posterior nucleus—related to taste & somatic
sensations like touch, pain, pressure, cold, heat, vibrations etc.

39. (2) Hypothalamus:
 The hypothalamus sits under the thalamus at the top of the
brainstem. Although the hypothalamus is small, it controls many
critical bodily functions:
• Controls autonomic nervous system
• Center for emotional response and behavior
• Regulates body temperature
• Regulates food intake(appetite)
• Regulates water balance and thirst
• Controls sleep-wake cycles
• Controls endocrine system
• Controls CVS regulation- Heart rate & BP
The hypothalamus is
shaded blue. The pituitary
gland extends from the
hypothalamus.

40. (3) Epithalamus & Pineal gland:
 Epithalamus is a small region superior & posterior to the
thalamus.
 It consist of pineal gland
 Pineal gland is about the size of the pea & protrudes from
posterior midline of the 3rd ventricle
 It’s a endocrine gland secrets hormone “Melatonin”.
 Darkness stimulates the pineal
gland to secrets melatonin—
it promotes sleepiness.

41. The cranial nerves:
 The 12 pairs of cranial nerves named because they
pass through bones of cranium & arise from the brain
inside the cranial cavity.
 These nerves may be sensory(carrying impulse to the
brain), motor (carrying impulse from the brain to
periphery) or mixed (containing both sensory & motor
fibers)

44. Thank you